For one thing they were so obsessed with security as a concept devleoping it that they completely ignored the use case of screen-readers for the visually impaired and prevent apps from accessing text from other apps and as far as I know it is still an issue.
By my understanding fuel cells are less about form factor, and more about directly converting the fuel into electricity across a membrane, like how batteries operate, so like a battery that takes in Hydrogen on one terminal and Oxygen on the other, being more efficient than burning it in an engine and trying to recapture some of that as electricity after thermal and friction losses have eaten into it.
So it is more a replacement for the engine than it is for the fuel tank. Wikipedia